The Communist Party confirmed Xi's second five-year term as president in October.
Xi, 64, is now required by the country's constitution to step down as president after two five-year terms.
Constitutional reform needs to be approved by parliament.
The People's Republic of China enacted its first Constitution in 1954.
"I think this is without a doubt the clearest confirmation we've had yet that Xi Jinping plans to stay in power much longer than we thought", said Jude Blanchette, an expert on Chinese politics in Beijing who works for The Conference Board, which provides research for companies.
Sunday's move will make Xi much more powerful than he already was, and will dampen any remnants of resistance to his rule, said Zhang Baohui, professor of worldwide affairs at Lingnan University in Hong Kong.
Although position that really matters in a China where Communist Party is above structures of State is that of Secretary General of CCP.
Canada Beats Czech Republic, Wins Men's Hockey Bronze At PyeongChang Olympics
But bronze-medal games typically have less to do with skill level, and more to do with which team decides to show up for the game. We are not saying it's impossible for Germany to win-that would be silly after what the team has done in the competition.
China's President Xi Jinping drinks wine as he makes a toast during a banquet in Hong Kong on June 30, 2017.
Next week, the party's central committee will hold a three-day plenum in Beijing that is expected to further strengthen Mr Xi's position by installing his allies as central bank governor and to lead the banking watchdog.
"This move is also not without risk for Xi", Howie said. "From anti-corruption campaign to comprehensively advancing the rule of law to profound economic restructuring, the CPC Central Committee with Xi at the core has sturdily opened a new era for a hopeful China".
Political analysts said the absence of an apparent successor pointed to Xi's longer-term ambitions.
The feared former head of the anti-graft agency, Wang Qishan, stepped down from the Standing Committee last October because at 69, he had reached the traditional retiring age. Wang, in the end, didn't remain on the PSC-though there's still a chance that he may not actually retire.
He is also the Chairman of China's Central Military Commission - a title, like that of Communist Party chief, that does not have a term limit.
After taking over a party general secretary, Xi has started a war against the corruption, which helped the country to improve its corruption perception ranking by Transparency International.
So my Chinese brothers and sisters, please do not be frightened by the communist party mafia, they have always been weak, relying on fear tactics to keep the proud chinese people as slaves to their whims.